I have used Howes Diesel Fuel Additives for the past two winters in my Volvo 770 Detroit series 60 12. 7 ltr engine. This truck has a model 382 fuel filter/water separator/fuel heater which a clear plastic top so it is easy to see the condition of the filter. In previous winters without using the Howes, filters were full and needed replacement at or about 15000 miles. Using the Howes for two winters now, filters last more than 75000 miles without a change. This saves me more than $450 in service costs. Howes diesel fuel conditioner typically retails for less than $10 and I use 2 jugs a week all winter. I can easily see in my saddle tanks and there is no evidence whatsoever of water although I know winter diesel fuel contains lots of water. Howes claim to fame is that it 'encapsulates' the water and passes it through the fuel system without damage to injectors. I would have to agree based on my experience.
Now I am using Howes diesel fuel conditioner all year round. At temps above 32 I just use half as much as is suggested on the bottle directions. You cannot overdose your engine with too much Howes!
I use Howes in my 2003 VW TDI and used it for 3 years in my Chev Duramax. I am waiting for delivery ofa new Dodge Ram Cummins 600 3500 SRW LBx and expect to use it if this truck is ever delivered (waiting 9 weeks now with a VIN# but no build date).
I have no experience with their Meaner Power Cleaner which claims to keeping injectors clean etc. It costs more, takes more for my tank size and I have no present need for what they claim it does.
As I understand it, the most important thing is to choose a product that does NOT contain alcohol! Howes does not contain alcohol according to their claims on the bottle.
It works just fine for me!